wardrobe vs furniture

wardrobe and furniture both are nouns.

Word	Noun	Adjective	Verb	Adverb
wardrobe	Yes	No	No	No
furniture	Yes	No	No	No

As nouns, furniture is a hypernym of wardrobe; that is, furniture is a word with a broader meaning than wardrobe:

wardrobe: a tall piece of furniture that provides storage space for clothes; has a door and rails or hooks for hanging clothes
furniture: furnishings that make a room or other area ready for occupancy

Other hypernyms of wardrobe include article of furniture, piece of furniture.

wardrobe (noun)	furniture (noun)
a tall piece of furniture that provides storage space for clothes; has a door and rails or hooks for hanging clothes	furnishings that make a room or other area ready for occupancy
collection of clothing belonging to one person
collection of costumes belonging to a theatrical company